Clinton returns to campaign trail with Trump rising in polls

By Amanda Becker GREENSBORO, N.C. (Reuters) - Hillary Clinton got back on the campaign trail on Thursday after taking three days off for pneumonia, and the Democratic presidential candidate faced a more challenging political landscape, with Republican rival Donald Trump rising in opinion polls. Senior Clinton aides said they always expected the race to the Nov. 8 election to be close. Clinton, 68, appeared in good health on a visit to the press section of her campaign plane while flying to Green